Question

Find the product. (3p – 7)(3p + 7)

A. 9p^2 + 49

B. 9p^2 – 42p – 49

C. 9p^2 + 42p + 49

D. 9p^2 – 49

Answer 1

(3p - 7)(3p + 7) =
(3p × 3p) + (3p × 7) + (-7 × 3p) + (-7 × 7) =
9p^2 + 21p - 21p - 49
= 9p^2 - 49

Therefore, answer would be D.

Answer 2

Explanation:

to multiply the two factors we can use the concept of FOIL

so when we multiply the (3p – 7)(3p + 7)

we get

`(3p -7)(3p + 7) = 3p.3p+3p.7-3p.7-7.7`

`9p^2-21p+21p-49` (cancel the 21p)

`9p^2-49`

correct option is D.